How a Wisconsin Case Before Justices Could Reshape Redistricting

The Wisconsin State Capitol in Madison. On Tuesday, the United States Supreme Court will hear a redistricting case from Wisconsin that could remake a polarized political landscape. Credit Michael P. King/Wisconsin State Journal, via Associated Press

WASHINGTON — How egregiously can a majority party gerrymander a political map before it violates the Constitution?

The Supreme Court has tried to answer that question for 30 years. On Tuesday, it will try again, hearing arguments in a case involving the Wisconsin State Assembly that could remake an American political landscape rived by polarization and increasingly fenced off for partisan advantage.

Republicans declared a strategy in 2008 to capture control of state legislatures so that they could redraw congressional districts to their advantage after the 2010 census. Political scientists said that was one reason the Democratic presence in the House of Representatives had fallen to 75-year lows. After November’s election, Democrats took steps to reclaim legislatures before the 2020 census set off a new round of map drawing.

In essence, the court is being asked to decide whether such a partisan divide should continue unabated or be reined in. The immediate stakes are enormous: A decisive ruling striking down the Wisconsin Assembly map could invalidate redistricting maps in up to 20 other states, said Barry C. Burden, the director of the Elections Research Center at the University of Wisconsin-Madison. Other analysts said that at least a dozen House districts would be open to court challenges if the court invalidated Wisconsin’s map. Some place the number of severely gerrymandered House districts as high as 20.

The historic nature of the question is underscored by a swarm of briefs— 54, totaling perhaps a thousand pages — filed by those with an interest in the outcome.

“I think it’s huge,” said Edward B. Foley, the director of the online Election Law project at the Moritz College of Law at Ohio State University. Without guidance from the court, he said, gerrymandering “is like the German autobahn — do whatever you want, as much as you want. A red light from the court, or even a strong yellow light, puts the brakes on this.”

But Professor Foley and other experts say they have little idea whether the court will slow or stop runaway gerrymandering — or indeed, whether it even wants to be a traffic cop. Many justices have written that they believe the worst partisan gerrymanders are clearly unconstitutional, and only two years ago five justices called them “incompatible with democratic principles.” But 11 years before that, the court very nearly ruled that partisan gerrymandering was a problem that only politicians — not the court — could resolve.

The case to be heard on Tuesday, Gill v. Whitford, could settle that debate once and for all. The 54 friend-of-the-court briefs, from party elders and officeholders, social scientists, historians, constitutional lawyers and even a neuroscientist, help build powerful arguments on both sides. They show how complex the seemingly simple definition of an unconstitutional gerrymander really is — and how the justices could define it should they choose to.

Gill v. Whitford is straightforward enough: After taking control of Wisconsin’s Legislature and State Capitol in 2010, Republicans used computer models and voting data to redraw political boundaries in the Assembly, the Legislature’s lower house. The map cemented the Republican majority in place. In the three elections since, Democrats have never won more than 39 of the 99 seats, even when they won a majority of the votes cast statewide for Assembly candidates.

The argument against that map can be traced to the most significant decision on political boundaries: the Supreme Court’s ruling, in 1964, that political districts must contain roughly equal numbers of people. (In the state at issue, Alabama, some State Senate districts contained as many as 41 times the number of voters of others.) Every vote must carry equal weight, the court stated; to dilute some voters’ voices by packing them into more populous districts violated the Equal Protection Clause of the Fourteenth Amendment.

That one-person-one-vote debate, which began two years earlier with the landmark case Baker v. Carr, was among the most fractious of the 20th century because the dissenters saw it as a disastrous intrusion into the domain of legislators — a “political thicket” that would inevitably politicize the court.

Now the court is as politicized as any in memory, cleaved into four reliably liberal justices who presumably favor limits on gerrymanders and four conservative justices who may want to let politicians decide. One justice — Anthony M. Kennedy, nominated by President Ronald Reagan and seated in 1988 — has denounced partisan gerrymandering but has wondered aloud whether the court could find a way to remedy it.

In the Wisconsin case, the plaintiffs — a band of Democrats backed by local lawyers and an advocacy group, the Campaign Legal Center — seek to expand the one-person-one-vote principle to partisan gerrymanders. By drawing a legislative map that effectively guarantees Republican victories in many Assembly districts, they say, Republican legislators rendered Democratic votes worthless, or at least worth less than Republican ones. That violates not only the Equal Protection Clause, they contend, but also the First Amendment, because it amounts to government-ordered punishment of Democrats for expressing their political preference at the ballot box.

The arguments are not new. The court itself has agreed that some partisan gerrymanders could violate the Equal Protection Clause. But it has also agreed that drawing political boundaries is unavoidably a political job and that some amount of partisanship is acceptable.

That makes the real question — the one that has tied the court in knots for three decades — tougher: Can the justices devise a yardstick that reliably measures when a gerrymander oversteps constitutional bounds? Or would that overstep the court’s own bounds and plunge it deeper into the political thicket of legislative duties?

Opponents of gerrymanders say the answer is clear. “The court can construct a cause of action that reliably flags extreme partisan gerrymanders, while placing meaningful constraints on judicial intervention,” the Brennan Center for Justice at the New York University School of Law argued in its brief. “Precisely because extreme partisan gerrymandering subverts normal politics, it cannot be addressed by normal politics.”

To which the Republican State Leadership Committee replied, “A holding in their favor would politicize the courts and would go far beyond intervention in the ‘political thicket’; it would impale the judiciary on its thorns.”

Justice Kennedy, by all accounts the crucial vote in the Wisconsin case, crystallized the court’s dilemma in a 2004 opinion, Vieth v. Jubelirer. The court said in 1964 that the goal of redistricting was “fair and effective representation for all citizens,” he wrote, but it has never defined what that means. Because of that, “we have no basis on which to define clear, manageable and politically neutral standards” for deciding when partisanship becomes unfair.

Justice Kennedy noted then that computer technologies were revolutionizing the redistricting process, allowing parties to design virtually unassailable gerrymanders with data and software unavailable in decades past. “These new technologies may produce new methods of analysis that make more evident the precise nature of the burdens gerrymanders impose on the representational rights of voters,” he added.

That statement has proved to be the rallying cry for gerrymandering opponents. The plaintiffs in the Wisconsin case prevailed in Federal District Court last year in part by offering a new data-driven yardstick for partisanship, the efficiency gap. Using that metric to compare the Republican map of the Wisconsin Assembly with nearly every other state redistricting plan from 1972 to 2014, the plaintiffs deemed the Wisconsin plan more partisan than all but four others.

Wisconsin government lawyers and their supporters excoriate the efficiency gap in their briefs, calling it a blunt instrument that would have struck down a third of all state plans during that period, including one Wisconsin plan drafted by a federal court. But before the Supreme Court, the plaintiffs and their backers are offering a flock of new yardsticks: the mean-median difference, the partisan symmetry principle and, not least, a software-driven measure that compared the Republican Assembly map with thousands of other maps that could have been drawn using the same data. All of them rate the Assembly map as a partisan outlier.

Wisconsin’s defenders deride the metrics as a “social science stew.” The plaintiffs’ reply: The court regularly dines on such a stew, using different measures of population deviation and racial polarization gauges to resolve other districting disputes.

Professor Foley of Ohio State wrote this week that Gill v. Whitford may be the rare case in which some of the justices file in for the oral argument with their minds still not made up, open to a skillful orator or a deft reply to a question. Others speculate that the justices, buried in briefs and mounds of statistics, could throw up their hands in despair at the range of options facing them.

Or they could simply punt, rejecting the plaintiffs’ argument on technical grounds, such as lack of standing, that Wisconsin’s lawyers have raised in their brief. Other partisan gerrymander cases are waiting in the wings; one of those may look to the justices like a better vehicle for a ruling.

Opponents of partisan gerrymanders say, however, that time is fast running out in a nation that seems almost daily to grow more bitterly divided and less willing to follow the rules of political comity.

“The norms that might have made it inappropriate to baldly pursue national partisan advantage, regardless of all constraints, have just been eroding,” Richard H. Pildes, a professor of constitutional law and an election-law expert at New York University, said in an interview.

“I think this is a very important moment for the democratic system in the United States. That’s not to say a court decision striking this gerrymander down is going to address all the problems we’ve got,” Professor Pildes said. “But in the absence of some sense of constitutional boundaries, the pathologies of this process are just going to grow and grow.”

A version of this article appears in print on October 2, 2017, on Page A16 of the New York edition with the headline: Justices Face Wisconsin Case That Could Redraw Partisan Political Maps.